Voltage-to-current converters are used in many electronic applications. In some of these applications it is desired to generate a current signal in response to an input voltage signal. Conventional voltage-to-current converters may only respond linearly to input voltage signals within a voltage range that is smaller than the entire voltage range generated by a direct current (DC) power supply that drives the voltage-to-current converter. For example, a phase-locked loop may include a voltage-to-current converter that provides a current signal to a current-controlled oscillator in response to a control voltage signal.
Thus, a need exists to provide a voltage-to-current converter that has a substantially linear current/voltage characteristic over substantially the entire range of a DC power supply voltage signal.